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Big Plays Win Games

| August 12th, 2019

What if I told you that less than 14% of plays determine the outcome of most NFL games?


Everybody loves watching big plays in football. Highlight reels are filled with bone-crushing sacks, long runs, deep bombs to a streaking WR, and big interceptions, because those are the exciting plays fans love to watch.

It turns out those are the plays that decide games too, and I have the stats to prove it.


Methods

Earlier this offseason, I wrote about the strong correlation between long runs and passes and overall offensive success, which got me thinking about what other plays might prove to be crucial to a team’s success. I ended up settling on four types of plays, which I will briefly describe below:

  • Explosive run: a carry that goes for 15+ yards
  • Explosive pass: a pass that goes for 20+ yards
  • Sacks
  • Turnovers

My hypothesis was that the team who produces more of these big plays than their opponent will usually win the game. To test this, I tracked all four categories for all 256 NFL games in 2018, along with the final score of each game.


Results

Teams that produced more big plays went 178-52 in 2018, good for a winning percentage of 77%.

That’s pretty remarkable when you consider that these plays accounted for less than 14% of all plays from scrimmage – not even considering special teams – and yet matched the winner 77% of the time. (Side note: if you’re doing the math and finding 178+52 is only 230, not 256, that’s because 26 games either ended in a tie or had both teams produce the same number of big plays).

I also looked at the season-long big play differential for teams compared to the number of games they won, which can be seen in the chart below.

As you can see, there’s a decent pattern there, which can be quantified with a correlation of 0.59. Generally, teams that won more games produced more big plays and/or gave up fewer big plays, which led to them winning. For the 2018 Bears, for instance, they led the NFL in both defensive big plays produced and limiting offensive big plays against them, and did a good job of avoiding sacks. That combination gave them a big play differential of +42, 2nd best in the NFL, even though they were below average in producing explosive plays on offense.

Now I realize this isn’t exactly a revolutionary conclusion – teams with more big plays win more games, duh! – but I think it’s useful to have numbers quantifying just how strong the relationship is. I know I was not expecting it to be this high.


Turnovers

There’s been a lot of work done over the years at the importance of winning the turnover battle, so I also checked this against just turnovers to see if it was any sort of improvement. At first glance, it doesn’t seem to be. In 2018, the team that won the turnover battle won 74% of the time, and historically that number has stayed fairly consistent in the 75-80% range, which is right around the 77% for big plays in 2018.

A closer look reveals that looking at total big plays, not just turnovers, can be helpful though. To understand why, let’s break up the turnover differential based on how close it was.

  • 2+ turnover margin: teams that won the turnover battle by 2 or more went 77-15 (84%) in 2018. There’s really not much improving on that, so let’s just say that winning the turnover battle by 2+ should win you the game. I will note, however, that 7 of the 15 losers in this category had a neutral or negative big play differential overall.
  • +1 turnover margin: Teams that won the turnover battle by exactly 1 went 64-34 (65%) in 2018. That’s pretty good, but here is where expanding to look at all big plays can be useful. In these 98 games, teams that won the big play differential won 76% of the time (66-21), a nice improvement from 65% when only looking at turnovers.
  • Even turnover margin: When the turnover margin is 0, teams win 50% of the time by definition, because every game has a winner and loser. This happened in 64 games in 2018, and in that group of games, the team that won the big play battle won 67% of the time (40-19).

This makes pretty good sense, at least to me. When a team wins the turnover margin convincingly, they should win the game. If the turnovers are close or even, other big plays have a larger role in determining the winner. Again, there’s nothing revolutionary in the conclusion, but I was a bit surprised by how convincing the relationship is.


Connections to 2019 Bears

Chicago won in 2018 despite a less-than-explosive offense because their defense was really good at generating turnovers and avoided giving up big plays. They’re very likely going to force fewer turnovers in 2019, and Chuck Pagano’s more aggressive style will likely leave them exposed to giving up more big plays as well. That means they’ll have to produce more explosive plays on offense if they want to remain among the best teams in the NFL.

The good news is that there are several reasons to think that will happen:

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